We have very few pilots visit the Tower where I work, despite it being attached to the terminals, so location is not necessarily the issue! I don't think it's something that a lot of pilots are interested in doing for some reason.
The few that have made the visit and stayed for an hour or so to plug in, say they have found it worthwhile, if only to appreciate why speed control is issued , or why they can't always be number 1!
louby